Buggy code:
public class TriviaGUI implements WindowListener { protected static final String WIKI_URL = "https:////sites.google.com//a//kneedeepintheses.org//information//Home" ; protected static final String ISSUES_URL = "https:////github.com//bubba0077//Trivia//issues" ; protected static final String KVSC_URL = "http:////www.kvsc.org//trivia_news.php" ; protected static final String VISUAL_URL = "https:////sites.google.com//a//kneedeepintheses.org//information//visual-trivia//visual-trivia-" ; protected static final String AUDIO_URL = "http:////trivia.bgsh.org//audio" ; private static final String FONT_FILENAME = "fonts//tahoma.ttf" ; private static final String DEFAULTS_FILENAME = ".trivia-defaults" ; private static final String SETTINGS_FILENAME = ".trivia-settings" ; private static final String SETTINGS_VERSION = "11" ; private static final Calendar TIME = Calendar . getInstance ( ) ; private static SimpleDateFormat TIMESTAMP_FORMAT ; protected static final String NEW_ANSWER_SOUND_FILENAME = "audio//NewAnswerSound.wav" ; public static final Properties PROPERTIES = new Properties ( ) ; private static final Hashtable < String , String > TAB_DESCRIPTION_HASH ; private final TriviaClient client ; private WaitDialog waitDialog ; private ArrayList < Integer > qNumberFilter ; private Pattern filterText ; private volatile TriviaGUI . QueueSort queueSort ; public TriviaGUI ( final String serverURL ) { } public static void main ( String [ ] args ) { } public TriviaClient getClient ( ) { } private final ArrayList < TriviaFrame > windowList ; public int getNTriviaWindows ( ) { } public TriviaMainPanel getTab ( TriviaFrame frame , String tabName ) { } public void loadProperties ( ) { } public void log ( String message ) { } public String nextWindowName ( ) { } public void registerWindow ( TriviaFrame frame ) { } public void resetProperties ( ) { } public void unregisterWindow ( TriviaFrame frame ) { } public void updateGUI ( final boolean force ) { } @ Override public void windowActivated ( WindowEvent e ) { } @ Override public void windowClosed ( WindowEvent e ) { } @ Override public void windowClosing ( WindowEvent e ) { } @ Override public void windowDeactivated ( WindowEvent e ) { } @ Override public void windowDeiconified ( WindowEvent e ) { } @ Override public void windowIconified ( WindowEvent e ) { } @ Override public void windowOpened ( WindowEvent e ) { } public static String getTabDescription ( String tabName ) { } public static Set < String > getTabNames ( ) { } public static void loadDefaults ( ) { } public static void savePosition ( Window window ) { } static void savePropertyFile ( ) { } public synchronized void disconnected ( ) { } protected void endProgram ( ) { } public static String ordinalize ( int cardinal ) { } public boolean isHideClosed ( ) { } void setHideClosed ( boolean hideClosed ) { } public boolean isHideDuplicates ( ) { } void setHideDuplicates ( boolean hideDuplicates ) { <START_BUG> TriviaGUI . PROPERTIES . setProperty ( "HideClosed" , ( hideDuplicates + "" ) ) ; <END_BUG> this . updateGUI ( true ) ; } public boolean isMute ( ) { } void setMute ( boolean mute ) { } void resetNumberFilter ( ) { } void resetTextFilter ( ) { } public Pattern getFilterText ( ) { } public ArrayList < Integer > getFilterNumbers ( ) { } void showNumberFilterDialog ( ) { } void showTextFilterDialog ( ) { } public TriviaGUI . QueueSort getQueueSort ( ) { } public void setQueueSort ( TriviaGUI . QueueSort queueSort ) { } private class NumberFilterDialog extends TriviaDialogPanel { private static final long serialVersionUID = - 3726819964211373465L ; private final JCheckBox [ ] checkboxes ; private static final int nPerColumn = 5 ; public NumberFilterDialog ( ) { } @ Override public void windowClosed ( WindowEvent event ) { } } private class TextFilterDialog extends TriviaDialogPanel { private static final long serialVersionUID = - 3726819964211373465L ; private final JTextField textField ; public TextFilterDialog ( ) { } @ Override public void windowClosed ( WindowEvent event ) { } } public static enum QueueSort { TIMESTAMP_ASCENDING , QNUMBER_ASCENDING , STATUS_ASCENDING , TIMESTAMP_DESCENDING , QNUMBER_DESCENDING , STATUS_DESCENDING ; } }

Fix:
TriviaGUI . PROPERTIES . setProperty ( "HideDuplicates" , ( hideDuplicates + "" ) ) ;